Polycyclic aromatic oxygen heterocycles

Polycyclic aromatic compound Polycyclic aromatic hydrocarbon Polycyclic aromatic sulfur heterocycle Polycyclic aromatic oxygen heterocycle Nitrogen-containing polycyclic aromatic compound (both heterocyclic and nonheterocyclic compounds) Secondary-nitrogen polycyclic aromatic nitrogen heterocycles (nitrogen in a five-membered ring)... 

The main types of substrates investigated so far are polycyclic aromatic compounds, aryl substituted carbo- and heterocyclic pentadienes, cyclic 1,3-dienes, furans, and olefins. It has turned out that type II photooxygenation of these compounds in solution occurs via the oxygen-activation mechanism. 

Schmid, E. R., G. Bachlechner, K. Varmuza, and H. Klus, Determination of Polycyclic Aromatic Hydrocarbons, Polycyclic Aromatic Sulfur, and Oxygen Heterocycles in Cigarette Smoke Condensate, Fresenius Z. Anal. Chem., 322, 213-219 (1985). 

Schmid ER, Bachlehner G, Vermuza K, Klus H (1985), Fresenius Z. Anal. Chem. 322 213-219.. .Determination of polycyclic aromatic hydrocarbons, polycyclic aromatic sulfur and oxygen heterocycles in cigarette smoke condensate"... 

Usually, coal tars are viscous liquids or semisolids that are black or dark brown with a naphthalene-like odor. Coal tars are complex combinations of polycyclic aromatic hydrocarbons (PAHs), phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. PAH composition of coal tars is variable. 

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Physically, they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. The coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. The coal tar creosotes consist of aromatic hydrocarbons, anthracene, naphthalene, and phenanthrene derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, dark brown to black residue which contains polycyclic aromatic hydrocarbons and their methyl and polymethyl derivatives, as well as heteronuclear compounds... 

Many fluorescence sensors are based, not on direct fluorescence, but on the quenching of fluorescence. Molecular oxygen, for example, is one of the best col-lisional quenchers. Oxygen can quench the fluorescence from polycyclic aromatic hydrocarbons complexes of ruthenium, osmium, iridium, and platinum and a number of surface-adsorbed heterocyclic molecules. An oxygen sensor can be made by immobilizing the fluorophore in a thin layer of silicone on the end of a fiber-optic bundle. Sensors for SO-, haliilcs, H-O-, and several other molecules have been ba.sed on fluorescence quenching. 

Coke-oven tar is an extremely complex mixture, the main components of which are aromatic hydrocarbons ranging from the monocyclics benzene and alkylbenzenes to polycyclic compounds containing as many as twenty or more rings. Heterocyclic compounds containing oxygen, nitrogen, and sulfur, but usually only one heteroatom per ring system are present. Small amounts of paraffinic, olefinic, and partly saturated aromatic compounds also occur. 

Xanthobacter polyaromaticivorans sp. nov. 127 W that degrades polycyclic and heterocyclic aromatic compounds under extremely low oxygen conditions. Bioscience, Biotechnology and Biochemistry, 68, 557—64. 

Polycyclic organic matter, derived from the total exhaust emission, is an extremely complex mixture. It includes a large number of compounds such as polynuclear aromatic hydrocarbons (PAH), derivations of PAH such as nitro-PAH and amino-PAH, oxygenated PAH such as phenols and quinones, and heterocyclic aromatic compounds containing sulfur and oxygen. In order to assist in the identification of classes of toxic compounds it is possible to fractionate the exhaust emissions into vapor and... 

Much of the interest in P450 IBl has been because of its ability to activate a very broad spectrum of chemical carcinogens, including polycyclic hydrocarbons and their oxygenated derivatives, heterocyclic amines, aromatic amines, and nitropolycyclic hydrocarbons [259] (Table 9.10,... 

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